30Tooth

iTrader: (1)

Look how close are the skirts to ground.

Nerobro

iTrader: (2)

The Chaparral people used lexan skirts, and just considered them disposable. On the 2J "vacuum car".

wtcc

iTrader: (2)

I was talking about his very unsuccessful car in the 1979 season not his brilliant Type 79 I don't need to google as I know a lot about it.

The problem is to convert this effect and the needed technology to a 1/10 rc tc. Even the real f1 cars of this era had many problems with skirts getting stuck or damaged. Now I (we) want to make it work in a much smaller scale doesn't make this task easy at all. I have to think how to prevent it getting stuck while still seal it properly and make it tough & light. Ideas welcome!

I also don't think that giving up on suspension won't hurt less than the now enhanced aerodynamics will better the laptimes. But it is worth a try. I will prepare the car to try it. It would be awesome if it worked, but I can't think how.

theVetteman3

iTrader: (3)

Nice work wtcc, this is getting in the ballpark of what I'm considering.

30Tooth

iTrader: (1)

Turnbuckles the length of the shocks lower the car the needed amount, only thing that matters in that case geometry wise will be caster, caster, ackermann and toe. Go extreme, have the car as low as you can (1mm if you can).

Nerobro

iTrader: (2)

you don't want to eliminate suspension movement...

Airwave

iTrader: (1)

from a far discussion with friends at my club track, I can remember with a touring configuration, we are close to the point such undertray will really have effect... Again, it is quite far but I think it was useless below 75 km/h.

ic-racer

This wind tunnel was used to test 1/12 scale Lexan RC bodies.

30Tooth

iTrader: (1)

Almost, there's still chassis flex so any one wheel bumps won't cause much trouble. If one would retain the suspension, high spring rates, low droop and higher roll centres to keep chassis motion in check are needed.

Seems too high of speed. Taking into account a 1/10th TC body has around 190cm2 of frontal area it displaces a fair amount of air at that speed.

Amazing! Thank you for sharing

I like this in particular:

Nerobro

iTrader: (2)

"This is what they used" That's a very, very, tiny tunnel for that body.

30Tooth

iTrader: (1)

It looks like it is, see the rapid airflow around mid cab? Nearest point to tunnel ceiling...

On the drawing board there is a Chaparral 2J inspired setup with one or two 380 powering one or two 80mm fans (go big or go home right?).

wtcc

iTrader: (2)

Found some time today to work on the "double chassis" idea to get both: a constant working airflow underneath while still having a working suspension.
I worked out a simple solution to attach the underfloor to uncouple it from the suspension movement by putting small screws into the underside of the suspension arms near the tires. This easy and fast idea takes out around 60-70% of movement, but less than I expected. Another problem is that I have an arched rear part of the floor because of the diffuser (and how I built it). So the front effect was pretty good, but the rear effect was poor.

Now what
I guess I have to rebuild the whole floor, need to buy a heat gun and use some other tools to make a perfect flat floor. The next step would be to utilize the (steering) hubs to attach the floor to. This way should lead to a satisfying airflow and chassis movement. May the force be with me



Edit: I did some changes to the floor today to try out the double chassis configuration. The attachment to the hubs is a challenge. The available space is hardly enough. Now all works out with around half a millimeter of space between wheel and hub.



This is how it looks right now. Next week I will start building an optimized floor with less cut out area for the front and a more nice geometry.

Got my excitement back. I wonder how the car will perform outdoor at high speeds with a sealed aero channel. Let the dust fly

30Tooth

iTrader: (1)

Looks great, post more pics of the underside please.

theVetteman3

iTrader: (3)

Those attachment pieces from the steering hubs to the floor, given their limited size, would probably benefit from being stronger and stiffer, like thicker lexan or carbon fiber. I really like this direction you're going, keep up the good work.

I have a few bodies I'm going to create under trays for. For scale looks only, I've got a Tamiya CLK GTR and 911 GT1. Those had flat bottoms and limited diffusers, but their construction will give me practice. I'm trying to determine which will be the best body candidate for aero experimentation. I'm looking at various Le Mans and Group C bodies.

30Tooth

iTrader: (1)

Indeed the Le Mans and Group C bodies are the best (I'm designing one for 235mm pan cars).
One very very important thing is DON'T trap air underneath, it will behave like a pillow and the car will lift. Vent it sideways (current LMP practice) or use a diffuser/rake the tray.